Commutator



Ami 7, 1925. v 1,532,129

E. A. FRIES COMMUTATOB Filed Fe 5. 1921 Patented Apr. 7, 1925.

UNITED STATES PATENT @FFEQE.

EDVARD A. FRIES, 0F DORCHES'IER, MASSACHUSETTS, ASSIGNOR, BY IJIESN E ASSZC-N- MENTS, TO FRANCIS J. V. DAKIN, OF BOSTON, IMASSACHUSETTS.

COMMUTATOR.

Application filed February 5, 1921.

Z 0 all whom it may concern:

Be it known that I, EDWARD A. Finns, a citizen of the United States, residing at Dorchester, in the county of Suffolk and State of Massachusetts, have invented a new and Improved Commutator, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to commutators and more especially to that type of commutators in which a contact carried by a rotating member is used for making and breaking the circuits.

The main object of the invention is the provision of a commutator which is simple in construction, efficient in operation and of a low cost of construction.

Another obj ect of the invention is the extension of the life of the device and to this end the movable contact is constructed with a plurality of contact surfaces which may be used up in their turn.

Other objects of the invention will be more specifically pointed out and described hereinafter.

Qne of the most important features of my invention resides in providing a movable contact member which is so made and adjusted that only a fractional part of its engaging surface is used at any one time and after the portion so used is worn out, the member may be arranged in another position to present a new engaging surface for use. By reason of this fact my commutator may be made to last indefinitely.

.Another important feature of the invention is that the engagement between the movable contact and the fixed contacts is'at all times a sliding engagement which con duces to smooth operation and good contacts and eliminates jumping or skipping so noticeable in a roll contact.

In the drawings Figure 1 is a plan View of a commutator constructed and operated in accordance with my invention; Fig. 2 is a sectional view on line 2-2 in Fig. 1; Fig. 3 is an end elevation of the sleeve and contact member shown in Fig. 2 and looking from right to left in that figure; Fig. 4 is a sectional view on line l4 in Fig. 3; and Fig. 5 is a view in perspective of the pin upon which the movable cont-act member is mounted.

Referring to the drawings illustrating one embodiment of my invention, desig- Serial 150. 442,685.

nates a casing open at the top and having a circular portion or flange 11. The lower part of the casing is cone-shaped and at the apex of the case is provided with a depres sion 12 to receive means for holding the casing in place when mounted for operation. On the inner side of the -flange ll of the casing is mounted a ring 14.- made of any suitable insulating material, having recesses for receiving fixed contacts 15. Each contact 15 is provided with a screw 16 which may be inte 'ral therewith and which projects outwaroly through a hole in the flange 11. The insulating ring 14 is held in place by the several contacts 15 which, in turn, are each securely fastened to the flange 11 by a nut 17 on the screw 16. A washer 18 having an inner flange and made of insulating material is mounted on the screw 16 between the nut 17 and flange 11, the inner flange of the washer l8 projecting into the hole through the flange 11 to insulatethe crew 16 therefrom. Preferably the top surfaces of the ring 14- and contacts 15 are bevelled to form a smooth continuous surface adapted to be engaged by a moving contact for making and breaking the circuits. In the drawings, the commutator is shown as having four fixed contacts 15 but this number may be increased or decreased to suit the requirements of the'particular use for which it is designed.

Projecting into the centre of the casing 10 is a timer shaft 20 upon the end of which is fastened a sleeve 21 having an integral radial arm 22 for carrying a movable contact. The timer shaft, the end only of which is shown in the drawings (Fig. 2,) may be operated by any suitable means. When the commutator is used in connection with an automobile engine, this shaft is rotated by suitable gears from the main shaft of the engine and'in synchronism with it, which construction is well known and unnecessary to illustrate. The sleeve 21 may be looked upon the timer shaft 20 by any suitable means such as a pin 24 lying in an open slot 25 in the sleeve and projecting into the shaft 20. A ring 26 right-angled in cross-section may be arranged on the shaft 20 and held there by a nut 28 in such position as to engage the end of the sleeve 21 and to overlap it in order to cover up the head of the pin 2a and to hold the lat ter against withdrawal.

In the arm parallel to the shaft 20 is set pin 30, upon which is loosely mount ed a circular cup-shaped disk contact 32, (see Fig. 4), held thereon by a washer 33 over which the end of the pin 30 is headed. The side of the washer may be bent upwardly at 3 in order to tilt the contact and a helical spring 35 is mounted on the pin between the contact and the radial arm 22. This spring should preferably be very light so that the disk contact 32 may not be pressed too strongly into engagement with the contacts 15 and generate friction. 'lhe pin 30 adjacent the arm 22 for a short distance is circular in cross-section and then is square in cross-section until the lower end is reached when it again assumes a round form to receive the washer 33 and to permit the end to he headed over the washer. In Fig. 5, being a perspective view 01 the pin, 37 indicates the rounded por tion adjacent the arm 22, 38 the square portion of the same diameter as 3?, and 39 the end to be headed by slightly reduced diameter. The contact 32 is provided with a central square hole which is slightly larger than the square portion oi the pin 30 and since the contact is normally held on that square portion 38 at all times by the spring 35 it follows that it cannot rotate on the pin but may tilt in any direction.

lfteferring to Fig. 1, it will be observed that the contact 15 is engaged by the outer portion only of the contact 32. Whcn that portion is worn down the contact may be moved upwardly on the pin 30 compressing the spring within the cup-like cavity of the contact a d when it has reached the circular portion of the pin, the contact may then be turnedfreely a quarter revolution and released. The spring 35 then forces it back into normal position on the square section of the pin and a new en aging surface is presented to the fixed contacts. This operation may be repeated until four difierent surfaces have been presented in turn which in eliect quadruples the life of the commutator.

The operation of my commutator is as follows. lVhen it is used in connection with an internal combustion engine, as for instance, on an automobile, the casing is arranged with the flanges 11 in a circular hole in the engine casing or frame and the casing is held there by a spring or other means engaging the depression 12. Secured to the outside of the casing is a bracket lO, carrying a collar 4-2 adapted to receive a pin (not shown) whereby through suitable connections with the spark-lever on the steering wheel the casing may be turned in either direction in order to advance or re tard the spark. The method of mounting the casing and the connections for advancing or retarding the spark are of usual term and well known and, therefore. have not been shown in the drawings. 'lhc various parts are adjusted on the timer shaft, as shown in Fig. 2, so that the outer side of the contac 32 is tilted away from the washer by its engagement with the insulatingring 14 and lined contacts 15, compressing the spring The fixed contacts are then connected by suitable electrical conductr .i, to their respective spark plugs in the cylinder off the engine, ti o fined contacts lei-ining one terminal or the circuit and able contact 32 the other tern" starting of the engine causes the t. to rotate and the arm carries the co around the insulating ring l and breaking in sequence the \a:ious ch curts as the contact 32 engages and disengages he various lined contacts 1!".

it is to he observed that the adjust itseli to irregularities which be due to uneveimess oi? wear ill the insul contact l memvirtue oi this universal n10.

ing material and the lirie hers. By ment of the niovahle cont/L or hreahiug oi the contact .i nated.

the spring spring should to hold the r n' insulati 5;; ring and overcome vii 'ations o any in tnis connectio ie by the u may he regulated on the timer shaft 20, tion of the sleeve 2i on the it will further be noticed a altei disk contact has worn slightly a cxlic" fiat surt'ace is 1 contact is secured. fit the same time the sliding engagement tends to keep the engaging SlllluCdS or all the contacts clean and smooth.

Although I. have shown and described a commutator in which the movable contact is so arranged that four different contact'in surfaces may be presented one after th other yet it may he so made that a larger nrnnher of contacting surfaces may he used by slightly enlarging the dish contact and by providing the pin with a section which is pentagonal or hexagonal in or section.

It is to he understood that my invention is not to he limited to the particular form herein shown and described since it may he embodied in other constructioi'is all within the purview of the invention.

ii'hat I claim is 1. In a commutator, the combination cl? lziu a plurality of fixed contacts set in a ring of insulating material, a rotatable member centrally disposed with respect to said contacts, a contact carried by said rotatable member for slidably engaging said fixed cantacts, and resilient means for holding said contact in engaging position; said con tact being so mounted as to be capable of tilting on its support in all directions without rotating.

2. In a commutator, the combination of a plurality of fixed contacts set in a ring of insulating material, a rotatable member centrally disposed with respect to said contacts, a circular contact carried by said rotatable member and loosely mounted thereon for slidably engaging said fixed contacts, said circular contact being capable of til"- ing in all directions but being held against rotatable movement and a spring for holding said circular contact in engaging position.

3. In a commutator, the combination of a plurality of fixed contacts set in a ring of insulating material, a rotatable member centrally disposed with respect to said contacts, a radial arm on said rotatable member, a. pin carried by said arm, said pin being square in cross-section except adjacent to said arm where it is round in cross-section, a contact member loosely mounted in the square portion of said pin, said contact member having a square aperture slightly larger than said pin and a spring be tween said contactand said radial arm for holding said contact in engagement with said ring of insulating material.

l. in a commutator, the combination of a plurality of fixed contacts set in a ring of insulating material, a. rotatable member and a disc contact carried by said rotatable member for slidably engaging said fixed contacts; said disc contact being loosely mounted to permit tilting in all directions.

5. In a commutator, the combination of a plurality of fixed contacts set in a ring of insulating material, a rotatable member and a disc contact carried by said rotatable member for slidably engaging said fixed contacts; said disc contact being so mounted as to be capable of tilting in all directions and being normally non-turning but capable of being turned to present a new wearing surface when necessary.

6. In a commutator, the combination of a plurality of fixed contacts set in a ring of insulating material, a rotatable member, a pin carried by said rotatable member having its free end portion squared in cross section, a disc contact mounted on said pin, and resilient means for holding said disc contact forwardly on the squared portion of said pin; said disc contact being normally held against turning by said squared portion of said pin, but being capable of being retracted on said pin against said resilient means to permit said disc contact to be turned on said pin to present a new wearing surface.

7. In a commutator, the combination of a casing, a ring of insulating material having a bevelled surface, a plurality of fixed contacts set in said ring and having contact surfaces flush with said bevelled surface, a rotatable member centrally disposed in relation to said ring and said contacts, a disc contact loosely mounted on said rotat-able member but non-turning thereon and having one face bevelled for sliding engagement with the bevelled surface of said ring, and a spring for holding said disc in en gagement with said ring; said disc contact being so mounted on said rotatable memher that it may be turned to present a new wearing surface by retracting it on its mounting against the pressure of said spring.

In witness whereof, I hereunto set my hand this thirty-first day ofJanuary, 1921.

EDWARD A. FRIES. 

